If you have having issues connecting to the Internet through your district-issued iPad, ensure the GlobalProtect app is enabled.
Tap GlobalProtect. (You may have two icons; as of October 2018, this is the currently supported version below.)
If it looks like this, tap the shield-looking button to connect:
A properly connected iPad should look like this. If you are still having issues, tap the button to disconnect, then again to reconnect: